JPS597538B2 - Core support device for castings - Google Patents

Description

[Detailed description of the invention] The present invention relates to a foundry core support device.

For example, in centrifugal casting of pipes, in order to form a socket, a large diameter part 2 is formed on the inner surface of one end of a cylindrical rotating metal frame 1, and an annular sand mold is formed inside the large diameter part 2, as shown in FIG. Naru Nakako 3
Conventionally, this core 3 has been supported by being fitted onto a front lid 5 which is fixed to the inner periphery of one end of the rotary metal frame 1 by appropriate means such as a knock pin 4.

However, with such a support configuration, the core 3 is consolidated between the casting tube P and the front lid 5 due to solidification shrinkage of the molten metal, so it is difficult to remove the front lid 5 from the inner periphery of the core 3 after casting is completed. The casting process was difficult and took a long time, which was an impediment to improving casting efficiency.

Therefore, as shown in FIG. 2, the present applicant has previously developed an annular shape by positioning the core 3 on the outer periphery of the cylindrical portion 6 of the front lid 5 where the core 3 is fitted to the outside, at a location where the core 3 is most compacted. The slide member 7 is fitted onto the outside, and the slide member 7 and the front cover 5 are slid relative to each other at the initial stage of extraction, so that the core is extracted without being affected by compaction, and the front cover 5 and the core 3 formed as a result are We proposed a method in which the sand from the core 3 is released into the space between them so that it can be pulled out easily after that, but it still requires a large extraction force, so a front cover that can be extracted even with a smaller extraction force was proposed. was desired.

In view of such demands, it is an object of the present invention to provide a casting core support device that can extract the core from the inner periphery with an extremely small extraction force.

The core support device of the present invention includes an annular support frame, a cylindrical portion at one end slidably fitted into the annular support frame, and a tapered outer circumferential surface whose diameter gradually increases toward the other end. a movable cylinder body having;
A retaining ring having a divided portion in the circumferential direction that fits onto the tapered outer circumferential surface of the movable cylinder and whose outer circumference fits into the inner circumferential surface of the core, and the movable cylinder is biased toward one end thereof. A core fixing means for fixing and supporting the core by expanding the diameter of the retaining ring via the tapered outer circumferential surface, and conversely moving the movable cylinder to the other end side against the biasing force of the core fixing means. The fixing release means reduces the diameter of the retaining ring to release the fixation of the core, and by operating the fixing release means after casting is completed, a gap is created between the inner periphery of the core and the outer periphery of the retaining ring. This allows the core to be pulled out very easily regardless of its compaction.

Preferably, the core fixing means comprises an elastic biasing means such as a coil spring, and the fixing release means comprises a lever mechanism operated by a member that moves toward one end of the movable cylinder.

An embodiment in which the present invention is applied to a front cover of a centrifugal casting machine will be described below with reference to FIGS. 3 to 5.

10 is a front lid according to the present invention; 11 is a plate-shaped annular support frame; the annular support frame 11 has an annular protrusion 12 protruding from one side of its outer periphery; The inner periphery of the annular protrusion 12 is provided with the outer periphery of one end of the core 3. or are mated.

Further, the inner circumferential portion of the annular support frame 11 extends to the inner side in the radial direction than the inner circumference of the core 3.

13 has a tapered outer circumferential surface 14 whose one end cylindrical portion 13a is slidably fitted to the inner periphery of the annular support frame 11, and whose diameter gradually becomes thicker as it moves toward the other end 13b. A receiving plate 15 is screwed to the outer periphery of one end of the movable cylinder 13, which faces the inner periphery of the side surface of the annular support structure 11 opposite to the annular protrusion 12. They are externally fitted and fixed together by welding 16.

Further, the sliding portion of the annular support frame 11 and the movable cylinder 13 is provided with a rotation preventing means (not shown) such as a key to prevent relative rotation between the two.

Reference numeral 17 denotes a retaining ring whose outer periphery fits into the inner periphery of the core 3, and the movable cylindrical body 1 is attached to the inner periphery at one point in the circumferential direction.
A tapered inner circumferential surface 18 is formed to be slidably fitted onto the tapered outer circumferential surface 14 of No. 3.

As shown in FIG. 4, the retaining ring 17 and the annular support frame 11 are connected to each other by a connecting ring 20 via locking pins 19a and 19b, respectively, to prevent them from separating from each other. There is.

The connecting rings 20 are arranged at two diametrically opposed locations separated by 90 degrees from the divided portion of the retaining ring 17.

A shielding plate 20 is fixed to the other end surface of the movable cylinder 13 and extends outward in the radial direction so as to cover the other end 17b of the retaining ring 17. This prevents it from entering the sliding part between the ring and the retaining ring 17.

Compression coil springs 22 are arranged at a plurality of locations at appropriate intervals in the circumferential direction between the annular support frame 11 and the receiving plate 15, and move and bias the movable cylinder body 13 toward one end thereof. By enlarging the diameter of the core 17 through the tapered outer circumferential surface 14, a core fixing means for fixedly supporting the core 3 is constituted.

Reference numeral 23 denotes a lever mechanism as a fixing release means, which is also disposed at multiple locations in the circumferential direction between the annular support frame 11 and the receiving plate 15 and between the compression coil springs 22. 15, a bearing 24 provided on the outer periphery of the side facing the annular support frame 11, a bearing 25 provided on the inner periphery of the side of the annular support frame 11 facing the receiving plate 15, and these bearings 2.
4, 25, and its free end 26a is connected to the movable cylinder 13.
a lever 26 that passes through a through hole 27 provided in the one end cylindrical portion 13a and projects from the inner periphery of the one end cylindrical portion 13a;
an operating ring 28 that is slidably fitted into the inner periphery of the six-end cylindrical portion 13a and has a tongue-shaped recess 29 into which the lever two free end 26a is fitted; When moved toward one end, the annular support frame 11 and the receiving plate 15 come relatively close to each other, and as a result, the movable cylinder 13 moves relative to the other end with respect to the retaining ring 17, causing the retaining ring 13 to contract in diameter. The structure is such that the fixed support of the core 3 is released.

In the above configuration, when the core 3 is supported as shown in FIG. One end 17a of the retaining ring 17 is pressed against one side of the annular support frame 11, and the diameter of the retaining ring 17 is expanded so that its outer circumference is press-fitted onto the inner circumferential surface of the core 3.

Therefore, the core 3 is lined and supported by the retaining ring 17 and is pressed against the annular support frame 11, so that no gap is created between the two.

In addition, in this state of supporting the core 3, the retaining ring 17 is fitted so as to overlap the entire circumferential surface of the tapered outer circumferential surface 14, and the shielding plate 21 at the other end of the movable cylinder 13 is close to the other end 17b of the retaining ring 17. Since it is located and covers this, molten metal scattered during pouring will not get caught in the sliding part between the movable cylinder 13 and this retaining ring 17.

In this state, by pouring metal while rotating the rotary metal frame 1, a tube P having an inner periphery of the socket corresponding to the core 3 is centrifugally cast.

When the tubular body P solidifies and casting is completed, the front cover 10 is pulled out from the rotary metal frame 1, but the core 3 is separated between the tubular body P and the retaining ring 17 due to solidification and contraction of the tubular body P. The retaining ring 17 and the core 3 are tightly pressed against each other.

However, in the front cover 10 of , the retaining portion 3 of the working arm 30 is inserted into the operating ring 28 from the inside in the radial direction as shown by the arrow in FIG.
After engaging 0a, move the working arm 30 in the direction of arrow a as shown in FIG.
When the operating ring 28 is moved in the direction, the operating ring 28 moves to one end side of the movable cylinder 13, and as a result, when the core 3 and the annular support frame 11 are fixed to the rotating metal frame 1, the movable cylinder 13 The holding ring 17 is fitted into the core 3 and is connected to the annular support ring 11 by the connecting ring 20 to prevent movement, so that the holding ring 17 is prevented from moving toward the movable cylindrical body 11. The inner circumference of the core 3 and the retaining ring 1 are relatively slid toward the small diameter side along the tapered outer circumferential surface 14 of the core 3 and the outer circumference is reduced in diameter.
7, a gap δ is created between the outer periphery, the press-fitting state between them is released, and the front cover 10 is very easily pulled out from the rotating metal frame 1 as the working arm 30 moves in the direction of the arrow a. .

It should be noted that since the diameter of the retaining ring 17 needs to be reduced from the state in which it is fitted to the inner periphery of the core 3, there will be a gap between the end faces of the divided parts in the fitted state. The spacing may be 2π times the gap δ; for example, if δ is around 3, the spacing is 20 degrees or less, and if the spacing is about this level, there will be no problem in supporting the core 3.

Furthermore, if a problem arises due to the large spacing, the retaining ring 17 may be divided into a plurality of parts to reduce the individual spacing, and the divided pieces may be connected to each other so as to allow displacement in the radial direction.

In addition, although the above description has shown only the embodiment of the front lid of a centrifugal casting apparatus, it can be similarly applied to other core support devices such as a core support device in a pouring method.

According to the casting core support device of the present invention, as is clear from the above description, by moving the movable cylinder using the fixing release means after casting is completed, the holding ring that externally supports the core is compressed. Since the diameter can be increased, even if the core is consolidated due to solidification and shrinkage of the casting, the support device can be pulled out very easily.Moreover, when the core is fixed by the retaining ring, the retaining ring and the core are annularly supported. Since it is pressed into contact with the frame, there is no risk of creating a gap that will cause flash or a decrease in dimensional accuracy. Since the inner periphery of the retaining ring is fitted so as to overlap the entire surface of the mortise, there is no possibility that the molten metal that has been scattered between them will infiltrate and become stuck, ensuring stable operation over a long period of time.

[Brief explanation of the drawing]

1 and 2 are cross-sectional views of a conventional front cover for centrifugal casting, FIGS. 3 to 5 show an embodiment in which the present invention is applied to a front cover for centrifugal casting, and FIG. 3 shows a core Fig. 4 is a vertical sectional view similar to Fig. 3, cut at a position shifted in the circumferential direction, and Fig. 5 is a longitudinal sectional view showing the fixed and supported state. It is a longitudinal cross-sectional view cut forward. DESCRIPTION OF SYMBOLS 10... Front lid (core support device), 11... Annular support frame, 13... Movable cylinder body, 14... Tapered outer peripheral surface, 1
6... Receiving plate, 17... Holding ring, 18... Tapered inner peripheral surface, 20... Connecting ring, 21... Shielding plate, 22... Compression coil spring (core fixing means), 23... Lever mechanism (fixing release means), 24. 25...Bearing, 26...
- Lever, 28...operation ring.

Claims (1)

[Claims] 1 A cylindrical portion at one end of a movable cylinder having a tapered outer circumferential surface whose diameter gradually increases as it moves toward the other end is slidably fitted to the inner periphery of the annular support frame, and the movable cylinder A retaining ring having a circumferentially divided portion whose outer periphery fits into the inner peripheral surface of the core is fitted onto the tapered outer peripheral surface of the body, and a movable cylinder is disposed between the annular support frame and one end of the movable cylinder. A core fixing means for biasing the body toward one end and fixing the inner circumferential surface of the core by expanding the diameter of the retaining ring; What is claimed is: 1. A casting core support device, characterized in that a fixing release means for moving the retaining ring to the side and reducing the diameter of the retaining ring is interposed.